A large portion of relevant modules/templates have now been switched to cargo. Various usages of SMW throughout the wiki need to be replaced by the new functions, in particular item tables. If some pages do not show up but contain no errors, please null-edit them. To see how you can help with the port check out Path_of_Exile_Wiki:To-do_list/SMW_migration (and leave a comment on the talk page if you have questions).
As with other "Mana taken before Life" effects, this skill will deduct 10% of the damage that would be inflicted on the character's life is deducted from mana instead. If the character has insufficient mana, then the remainder of the damage will be taken from life. Damage dealt to energy shields will not be deducted from mana.
See Mind Over Matter for details on the mechanic.